Once you have downloaded the files, copy the .po and .mo files into the /opt/bitnami/apps/wordpress/htdocs/wp-content/languages directory. If this directory does not exist, create it manually as follows:

$ sudo mkdir /opt/bitnami/apps/wordpress/htdocs/wp-content/languages

Log in to the WordPress administration panel.

Click on the “Settings -> General” tab located in the menu on the left.

Scroll down until “Site Language”. The newly-installed language should now appear in the list. Select it and click “Save Changes”.